What are Asbestos. Risk of cancer while working with Asbestos.

Asbestos:

Asbestos is a set of six naturally occurring silicate minerals, which all have in common their eponymous asbestiform habit: i.e. long, thin fibrous crystals, with each visible fiber composed of millions of microscopic “fibrils” that can be released by abrasion and other processes.

Asbestos mining existed more than 4,000 years ago, but large-scale mining began at the end of the 19th century, when manufacturers and builders began using asbestos for its desirable physical properties. Some of those properties are sound absorption, average tensile strength, affordability, and resistance to fire, heat, and electricity. It was used in such applications as electrical insulation for hotplate wiring and in building insulation. When asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement or woven into fabric or mats. These desirable properties made asbestos very widely used. Asbestos use continued to grow through most of the 20th century until public knowledge of the health hazards of asbestos dust led to its outlawing by courts and legislatures in mainstream construction and fireproofing in most countries.

 

Inhalation of asbestos fibers can cause serious and fatal illnesses including lung cancer, mesothelioma, and asbestosis (a type of pneumoconiosis). Concern of asbestos-related illness in modern times began with the 20th century and escalated during the 1920s and 1930s. By the 1980s and 1990s, asbestos trade and use were heavily restricted, phased out, or banned outright in an increasing number of countries.

Despite the severity of asbestos-related diseases, the material has extremely widespread use in many areas. Continuing long-term use of asbestos after harmful health effects were known or suspected, and the slow emergence of symptoms decades after exposure ceased, made asbestos litigation the longest, most expensive mass tort in U.S. history though a much lesser legal issue in most other countries involved. Asbestos-related liability also remains an ongoing concern for many manufacturers, insurers and reinsurers. On July 12, 2018, a Missouri jury ordered Johnson & Johnson to pay a record $4.69 billion to 22 women who alleged the company’s talc-based products, including its baby powder, contain asbestos and caused them to develop ovarian cancer.

Types and associated fibers:

Six mineral types are defined by the United States Environmental Protection Agency (EPA) as “asbestos” including those belonging to the serpentine class and those belonging to the amphibole class. All six asbestos mineral types are known to be human carcinogens. The visible fibers are themselves each composed of millions of microscopic “fibrils” that can be released by abrasion and other processes.

The three main types of asbestos that you may come across whilst carrying out building work are:

  • Chrysotile (white asbestos). Chrysotile is the most commonly used type of asbestos and is often contaminated with trace amounts of tremolite. Chrysotile fibres are usually fine in texture, possessing high flexibility and good heat resistant properties, making it ideal for use in cement, brake pads/linings and roofing materials.
  • Amosite (brown asbestos). Mined mostly in Africa, amosite is a particularly strong and heat-resistant type of asbestos that was commonly used in cement sheet, plumbing insulation and electrical insulation. Though all types of asbestos are toxic, amosite asbestos exposure has a comparatively higher cancer risk.
  • Crocidolite (blue asbestos). Crocidolite has very thin fibres and, if inhaled, are easily lodged in the lungs. It’s thin fibres and brittle nature make crocidolite one of the most harmful forms of asbestos, as it easily breaks down and leads to asbestos exposure.

Other Minor Types of Asbestos:

There are three minor types of asbestos that you may hear about. Tremolite, actinolite and anthophyllite have never been sold commercially. Instead, they were often found as contaminants in commercially sold asbestos products.

Tremolite

Tremolite fibres are often found as a contaminant in chrysotile asbestos and found in paints, sealants, asbestos-containing insulation products and talc products. It can manifest in several colours, including white, green and grey, and is useful as it can be spun and woven into cloth.

Actinolite

Actinolite fibres are lightweight and generally dark in colour. It comes in various forms, including brittle and fibrous or dense and compact, and is often found in paints, sealants and drywall. Additionally, actinolite expands when heated, making it an effective insulation material. This property has led to actinolite being commonly used as insulation materials and structural fire-proofing.

Anthophyllite

Anthophyllite fibres are grey-brown in colour, commonly found as a contaminant in composite flooring. While anthophyllite is considered to be non-commercial, it was regularly used in products containing vermiculite and talc, such as talcum powder. Even though most studies suggest that the risk of developing mesothelioma from this type of asbestos is much lower than amosite, chrysotile and crocidolite asbestos, there is still a clear link between anthophyllite and the disease.

Uses of Asbestos:

Asbestos is a naturally-occurring, fibrous mineral that was predominantly used as a building material in the UK between the 1950s and 1980s. Mined in countries such as Russia, Brazil, South Africa and China, asbestos fibres were woven into fabrics or mixed in cement and used all around the world.

Materials made with asbestos are strong, incombustible, heat-resistant and sound-absorbent, making asbestos an attractive material for electrical and building insulation, among other uses.

In the UK, any building or material manufactured or refurbished before the year 2000 may contain asbestos. Therefore, you have an increased risk of encountering it when working on pre-2000 properties.

In 1999, the UK banned asbestos, due to an increased incidence of lung-related diseases in those working with the substance. Currently, over 50 countries prohibit the use of asbestos, but it’s still commonly used in some countries, such as India, China, Russia and Indonesia.

Cancer risk associated with Asbestos:

People can be exposed to asbestos in different ways:

  • Inhaling asbestos: Most exposures come from inhaling asbestos fibers in the air. This can occur during the mining and processing of asbestos, when making asbestos-containing products, or when installing asbestos insulation. It can also occur when older buildings are demolished or renovated, or when older asbestos-containing materials begin to break down. In any of these situations, asbestos fibers tend to create a dust made of tiny particles that can float in the air.
  • Swallowing asbestos: Asbestos fibers can also be swallowed. This can happen when people consume contaminated food or liquids (such as water that flows through asbestos cement pipes). It can also occur when people cough up asbestos they have inhaled, and then swallow their saliva.

Many people are exposed to very low levels of naturally occurring asbestos in outdoor air as a result of erosion of asbestos-containing rocks. The risk of this is higher in areas where rocks have higher asbestos content. In some areas, asbestos can be detected in the water supply as well as in the air. It can get into the water through several sources, such as rock or soil erosion, corrosion of asbestos cement pipes, or the breakdown of roofing materials containing asbestos that then enter the sewers after it rains.

However, the people with the heaviest exposure are those who worked in asbestos industries, such as shipbuilding and insulation. Many of these people recall working in thick clouds of asbestos dust, day after day.

Family members of asbestos workers can also be exposed to high levels of asbestos because the fibers can be carried home on the workers’ clothing, and can then be inhaled by others in the household.

Asbestos exposure is also a concern in older buildings. If building materials that contain asbestos (like older insulation and ceiling and floor tiles) begin to decompose over time, asbestos fibers can be found in indoor air and may pose a health threat. There is no health risk if the asbestos is bonded into intact finished products, such as walls and tiles. As long as the material is not damaged or disturbed (for example, by drilling or remodeling), the fibers are not released into the air. Maintenance workers who sweep up and dispose of the asbestos dust or handle damaged asbestos-containing materials are often exposed to higher levels than other people in these buildings. Removing asbestos from homes and other buildings can also cause some exposure, although modern asbestos abatement workers are trained to use proper protective equipment to minimize exposure.

Although use of asbestos has declined in the United States, people can still be exposed to asbestos in the workplace. In recent years, the US Occupational Health and Safety Administration (OSHA) has estimated that over a million American employees in construction and general industries face significant asbestos exposure on the job.

The mining and use of asbestos is also still a health hazard in some other parts of the world. Mining in the Russian Federation, China, Kazakhstan, Brazil, Canada, and Zimbabwe accounts for almost all of the world production of asbestos. Much of what is produced is used in the Russian Federation (and other countries in the former Soviet Union) and Asia, and its use is on the rise in some areas. In 2005, the World Health Organization estimated that about 125 million people worldwide were exposed to asbestos at work, despite the known links to cancer and other lung diseases for more than 60 years.

Asbestos and Cancer:

Researchers use 2 main types of studies to try to figure out if a substance causes cancer.

  • Studies in people: One type of study looks at cancer rates in different groups of people. Such a study might compare the cancer rate in a group exposed to a substance to the cancer rate in a group not exposed to it, or compare it to the cancer rate in the general population. But sometimes it can be hard to know what the results of these studies mean, because many other factors might affect the results.
  • Lab studies: In studies done in the lab, animals are exposed to a substance (often in very large doses) to see if it causes tumors or other health problems. Researchers might also expose normal cells in a lab dish to the substance to see if it causes the types of changes that are seen in cancer cells. It’s not always clear if the results from these types of studies will apply to humans, but lab studies are a good way to find out if a substance might possibly cause cancer.

In most cases neither type of study provides enough evidence on its own, so researchers usually look at both human and lab-based studies when trying to figure out if something causes cancer.

Evidence from studies in both people and lab animals has shown that asbestos can increase the risk for some types of cancer.

When asbestos fibers in the air are inhaled, they can stick to mucus in the throat, trachea (windpipe), or bronchi (large breathing tubes of the lungs) and might be cleared by being coughed up or swallowed. But some fibers reach the ends of the small airways in the lungs or penetrate into the outer lining of the lung and chest wall (known as the pleura). These fibers can irritate the cells in the lung or pleura and eventually cause lung cancer or mesothelioma.

Types of Cancers associated with Asbestos exposure:

There are mainly three types of cancers associated with Asbestos. All the three types are related to Mesothelium (protective layer surrounding the organs) of Internal organs like lungs, heart, abdomen. This type of cancer is called Mesothelioma Cancer. As the name indicates, this type of cancer mainly affect the mesothelium (the protective layer of the organs) of lungs, heart and abdominal parts. There are three kinds of Mesothelioma.

  1. Pleural Mesotheliom
  2. Pericardial Mesothelioma
  3. Peritoneal Mesotheliom

 

One Comment

Add a Comment

Your email address will not be published. Required fields are marked *